micro:bit Breakout Board Hookup Guide

Introduction

The micro:bit, by itself, offers a vast array of possibilities and potential projects, considering it includes an onboard temperature sensor, accelerometer, compass, LED array, Bluetooth radio, and more. However, when you’re ready to branch out beyond those initial capabilities, like connecting to an SD card for logging, you’ll need to break out some of the pins on the micro:bit’s card edge connector. For that, we’ve got you covered with the micro:bit Breakout Board.

Hardware Overview

The micro:bit Breakout board allows you to utilize all of the pins on the micro:bit and opens up some previously inaccessible communication ports, like I2C and SPI.

Top-down diagram of the micro:bit breakout board

Pins

Most of the micro:bit’s pins can be configured for one or more functions.

Pin

Function 1

Function 2

Description

GND

Ground

GND

Ground

3V3

3.3V

0

Analog In

Connected to large pin 0

1

Analog In

Connected to large pin 1

2

Analog In

Connected to large pin 2

3

Analog In

LED Column 1

Controls part of LED array

4

Analog In

LED Column 2

Controls part of LED array

5

Button A

Connected to Button A on micro:bit

6

LED Column 9

Controls part of LED array

7

LED Column 8

Controls part of LED array

8

Open GPIO pin

9

LED Column 7

Controls part of LED array

10

Analog In

LED Column 3

Controls part of LED array

11

Button B

Connected to Button B on micro:bit

12

Open GPIO pin

13

SCK

GPIO or SPI clock

14

MISO

GPIO or SPI MISO

15

MOSI

GPIO or SPI MOSI

16

Open GPIO pin

19

SCL

GPIO or I2 clock

20

SDA

GPIO or I2 data

Power Pin

The pin listed as 3V3 can be used as an input (regulated 3.3V, do not exceed 3.6V!) or an output if you plug a battery pack or USB into the micro:bit.

LCn Pins

The pins labeled with LCn (e.g. LC1, LC8) refer to pins that are used to control the LED array on the front of the micro:bit. You can use them as GPIO, but you’ll often get weird patterns to show up on the LEDs, or when you write to the LED array, you may see unexpected behavior. If you use them as GPIO, we recommend disabling the LED display.

Hardware Assembly

Attach Headers

If you have the version of the breakout board without headers, solder some breakaway headers to the board. You can also solder wire directly to the breakout.

Build Example Circuit

Note: The micro:bit must be facing up in order to make electrical connections to the pins.

To begin, let’s light up an RGB LED. Attach the micro:bit to the breakout board, place the breakout board onto a breadboard, and connect an RGB LED through 330 Ω resistors. Use the image below to aid you in wire up the circuit.

Remember, LEDs are polarized parts and can only work properly in one orientation. The longest leg of the LED goes where the black GND wire is in the circuit.

Having a hard time seeing the circuit? Click on the wiring diagram for a closer look.

Example: Cycling Colors on an RGB LED

You can download the code from the emulator, or check out the project’s page here:

Copy the .hex file to your micro:bit drive, and you should see a fancy array of colors appear on your LED!

Resources and Going Further

With the micro:bit breakout board, you can start introducing more sensors, lights, and motors into your project! For more information, check out these resources:

Here are a few tips in using the PicoBoard with Scratch v1.4. The PicoBoard allows us to write Scratch programs that interact with a variety of sensors on the PicoBoard. These sensors include: sound, light, a slider, a push button, and 4 external sensors (A, B, C, and D).

The TFMini is a ToF (Time of Flight) LiDAR sensor capable of measuring the distance to an object as close as 30 cm and as far as 12 meters! The TFMini allows you to integrate LiDAR into applications traditionally reserved for smaller sensors such as the SHARP GP-series infrared rangefinders.

In 2003, CU student Nate Seidle fried a power supply in his dorm room and, in lieu of a way to order easy replacements, decided to start his own company. Since then, SparkFun has been committed to sustainably helping our world achieve electronics literacy from our headquarters in Boulder, Colorado.

No matter your vision, SparkFun's products and resources are designed to make the world of electronics more accessible. In addition to over 2,000 open source components and widgets, SparkFun offers curriculum, training and online tutorials designed to help demystify the wonderful world of embedded electronics. We're here to help you start something.